diff options
Diffstat (limited to 'target/arm/cpu.h')
| -rw-r--r-- | target/arm/cpu.h | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 25f31a4e21..2b9740878b 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -538,19 +538,29 @@ typedef struct CPUARMState { /* scratch space when Tn are not sufficient. */ uint32_t scratch[8]; - /* fp_status is the "normal" fp status. standard_fp_status retains - * values corresponding to the ARM "Standard FPSCR Value", ie - * default-NaN, flush-to-zero, round-to-nearest and is used by - * any operations (generally Neon) which the architecture defines - * as controlled by the standard FPSCR value rather than the FPSCR. + /* There are a number of distinct float control structures: + * + * fp_status: is the "normal" fp status. + * fp_status_fp16: used for half-precision calculations + * standard_fp_status : the ARM "Standard FPSCR Value" + * + * Half-precision operations are governed by a separate + * flush-to-zero control bit in FPSCR:FZ16. We pass a separate + * status structure to control this. + * + * The "Standard FPSCR", ie default-NaN, flush-to-zero, + * round-to-nearest and is used by any operations (generally + * Neon) which the architecture defines as controlled by the + * standard FPSCR value rather than the FPSCR. * * To avoid having to transfer exception bits around, we simply * say that the FPSCR cumulative exception flags are the logical - * OR of the flags in the two fp statuses. This relies on the + * OR of the flags in the three fp statuses. This relies on the * only thing which needs to read the exception flags being * an explicit FPSCR read. */ float_status fp_status; + float_status fp_status_f16; float_status standard_fp_status; /* ZCR_EL[1-3] */ @@ -1190,12 +1200,20 @@ static inline void xpsr_write(CPUARMState *env, uint32_t val, uint32_t mask) uint32_t vfp_get_fpscr(CPUARMState *env); void vfp_set_fpscr(CPUARMState *env, uint32_t val); -/* For A64 the FPSCR is split into two logically distinct registers, +/* FPCR, Floating Point Control Register + * FPSR, Floating Poiht Status Register + * + * For A64 the FPSCR is split into two logically distinct registers, * FPCR and FPSR. However since they still use non-overlapping bits * we store the underlying state in fpscr and just mask on read/write. */ #define FPSR_MASK 0xf800009f #define FPCR_MASK 0x07f79f00 + +#define FPCR_FZ16 (1 << 19) /* ARMv8.2+, FP16 flush-to-zero */ +#define FPCR_FZ (1 << 24) /* Flush-to-zero enable bit */ +#define FPCR_DN (1 << 25) /* Default NaN enable bit */ + static inline uint32_t vfp_get_fpsr(CPUARMState *env) { return vfp_get_fpscr(env) & FPSR_MASK; |